This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Most analyses of tubulin dynamics and the study of tubulin binding proteins use tubulin isolated from bovine or pig brain. Although it is possible to purify the tubulin away from microtubule associated proteins by repeated rounds of polymerization and depolymerization, the tubulin itself has a heterogeneous collection of posttranslational modifications. We would like to compare our tubulin preps with commercially available tubulin preps and if possible look for posttranslational modifications in our tubulin prep.